In the conventional design of a backlight module, clamping hooks are used for positioning the frames, so as to save cost and reduce assembly time. As shown in FIG. 1, the backlight module includes a middle frame 300 and a back frame 400 of an LCD device. The middle frame of the LCD device includes holes 310. The back frame of the LCD device includes convex structures 410; and the holes are matched with the convex structures for positioning. In other designs, the holes are arranged on the back frame of the LCD device and the convex structures are arranged on the middle frame of the LCD device.
U.S. Pat. No. 6,976,781B2, published on Oct. 20, 2005, discloses a structural frame and a baffle of a backlight unit. The backlight unit includes a frame which includes a first edge and a second edge. A first hook on an outer surface of the first edge protrudes outwardly; and the outer surface of the second edge includes a first hole. The baffle includes a first side wall and a second side wall. The first side wall includes a second hole and the outer surface of the second side wall includes a second hook which protrudes outwardly. The frame is installed on the baffle. The first edge is arranged on the inner surface of the first side wall. The first hook is embedded into the first hole for fixing the frame and the baffle. The second hook is arranged on the surface of the second side wall and embedded into the second hole for fixing the frame and the baffle. Although the frames can be fixed using the above scheme, the strength of parts is reduced as a result of any hole on parts.